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Paragraph
he
Indian
Space
Research
Organisation
has
crossed
a
significant
milestone
with
the
successful
developmental
flight
of
the
country's
heaviest
Geosynchronous
Satellite
Launch
Vehicle,
the
GSLV
Mark-III.
This
is
the
first
time
a
satellite
weighing
over
3.1
tonnes
has
been
launched
from
India
to
reach
the
geostationary
orbit
about
36,000
km
from
Earth.
The
Mk-III
can
launch
satellites
weighing
up
to
four
tonnes,
which
almost
doubles
India's
current
launch
capacity.
With
communication
satellites
becoming
heavier
(up
to
six
tonnes),
the
capability
for
larger
payloads
is
vital.
This
can
be
done
by
switching
over
to
electric
propulsion
for
orbit
rising
and
to
keep
the
satellite
in
the
right
position
and
orientation
in
the
orbit
through
its
lifetime
(that
is,
station
keeping).
The
switch-over
would
reduce
the
weight
of
the
vehicle
as
it
can
do
away
with
nearly
two
tonnes
of
propellants
and
carry
heavier
satellites.
Towards
this
end,
ISRO
has
started
testing
electric
propulsion
in
a
small
way;
the
South
Asia
Satellite
(GSAT-9)
that
was
launched
last
month
used
electric
propulsion
for
station
keeping.
On
Monday,
an
indigenously
developed
lithium-ion
battery
was
used
for
the
first
time
to
power
the
satellite.
Another
key
achievement
is
the
use
of
an
indigenously
developed
cryogenic
stage,
which
uses
liquid
oxygen
and
liquid
hydrogen;
the
2010
GSLV
launch
using
an
indigenous
cryogenic
stage
ended
in
failure.
It
can
now
be
said
without
hesitation
that
India
belongs
to
the
elite
club
of
countries
that
have
mastered
cryogenic
technology.
In
the
December
2014
experimental
flight
of
the
GSLV
Mk-III,
a
passive
cryogenic
stage
was
used.
Though
the
cryogenic
stage
was
not
meant
to
be
ignited,
the
launch
provided
invaluable
data
on
aerodynamic
behaviour
of
the
vehicle.
The
Mark-III
will
be
operational
with
the
success
of
one
more
developmental
flight,
which
is
set
to
take
place
within
a
year.
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